Medical devices such as vascular and endovascular grafts and stent-grafts can include fabric components that provide various functions. For example, the fabric component of an endovascular device can function to promote sealing of the device to the lumen or structure in which it is implanted. Insertion of such devices and fabric components into target sites can require that the device and fabric component be passed through the lumen of a delivery catheter or cannula.
Conventional fabrics used for implantable medical devices generally utilize yarns having a linear density of about 40 denier or higher. As an example, a cardiovascular implant usable as a heart valve or for vessel repair can have a graft material about the perimeter of the implant that comprises 40 denier yarns. Implantable devices that include grafts having yarn densities in this range can typically be delivered through a 16-22 French catheter or higher on the French catheter scale. The French catheter scale (abbreviated as Fr) is commonly used to measure the outer diameter of cylindrical medical instruments including catheters. In the French system, the diameter in millimeters of the catheter can be determined by dividing the French size by 3. Thus, a decreasing French size corresponds with a smaller diameter catheter.
In certain medical circumstances, it may be desirable to use a smaller outer diameter catheter to deliver an implantable device. For example, it may be desirable to use a smaller diameter catheter in a patient having a smaller anatomical area through which a surgical site is accessed, such as by percutaneous means, or in a patient in which the anatomical location of repair is smaller than average. In order to utilize smaller diameter delivery catheters, the implantable devices delivered through such catheters need to be smaller as well. In particular, smaller diameter delivery catheters may require implantable devices having a smaller diameter.
Thus, there is a need for an ultra-thin fabric that can allow an implantable device to have a smaller overall diameter, thereby permitting the device to be delivered through a smaller diameter catheter. There is a need for such a fabric that can exhibit performance characteristics similar to those of thicker implantable fabrics.